1. Field Of The Invention
The invention relates to raw hide strips containing an anti-tartar agent. The invention also relates to a process of preparing such raw hide strips. The invention further relates to a process of preventing tartar formation on dogs, teeth by the dog chewing on such raw hide strips.
2. Background Art
Dental calculus, or tartar as it is sometimes called, is a deposit which forms on the surfaces of the teeth at the gingival margin. Supragingival calculus appears principally in the areas near the orifices of the salivary ducts; e.g., on the lingual surfaces of the lower anterior teeth and on the buccal surfaces of the upper first and second molars, and on the distal surfaces of the posterior molars. Mature calculus consists of an inorganic portion which is largely calcium phosphate arranged in a hydroxylapatite crystal lattice structure similar to bone, enamel and dentine. An organic portion is also present and consists of desquamated epithelial cells, leukocytes, salivary sediment, food debris and various types of microorganisms. As the mature calculus develops, it becomes visibly white or yellowish in color unless stained or discolored by some extraneous agency. In addition to being unsightly and undesirable from an aesthetic standpoint, the mature calculus deposits are constant sources of irritation of the gingiva and thereby are a contributing factor to gingivitis and other diseases of the supporting structures of the teeth, the irritation decreasing the resistance of tissues to endogeneous and exogenous organisms.
A wide variety of chemical and biological agents have been suggested in the art to retard calculus formation or to remove calculus after it is formed in humans. Mechanical removal of this material is done routinely in humans.
Chemical Technology: An Encyclopedic Treatment, Vol. V, Barnes & Noble Books, (1972), pages 392 to 406, is a general disclosure of types of leathers and their uses, and the tanning of leather. Arnold, John R., "Hides And Skins", (1925), pages 6, 7, 252, 253, 310 and 311, is a general disclosure on raw and tanned hides and skins.
Footwear And Leather Abstracts, Information Retrieval Limited, Vol. II, No. 1, (1967), page 61, discloses several methods for the depilation of skins and raw hides and for processing raw hide.
North American Packer Hides, Pratt Bros. Co., (1939), page 107, defines rawhide leather as being hides that have been limed, dehaired and stuffed with oil or grease, but otherwise not tanned. Flemming, Louis A., "Practical Tanning", (1910), pages 81 to 83, describes methods of making lace leather.
Churchill, James E., "The Complete Book Of Tanning Skins And Furs", (1983), pages 165, discloses how to make raw hide. Page 166 discloses that rawhide and objects made from rawhide will be eaten by dogs and other animals unless they are treated with mineral oil or another preservative.
Partridge, John, "Chemical Treatment Of Hides And Leather", (1972), pages 2 to 43, deals with the chemical preservation of raw hides and skins and the chemical dehairing of skins and hides. The treatments include: removing hair using a solution of lime containing an inorganic phospho-sulfur compound containing at least one P-S bond; and dehairing using enzymatic action with K.sub.2 HPO.sub.4 as a pH adjuster.
Thorstensen, Thomas C., "Practical Leather Technology", (1985), pages 1 to 41, deals with the preparation of hides.
Kirk-Othmer, "Encyclopedia Of Chemical Technology", 3rd Ed., Vol. 14, (1981), pages 200 to 216, is a general article on leather. Pages 213, 215 and 216 disclose that polyphosphates are excellent pretannages for vegetable tanning. Optimum molecular weights of the polyphosphates are from 1500 to 2500. Also there is a minimum-effluent vegetable tanning system, known as the Liritan process. The limed and bated hides are treated for 24 hours in a pit with 5 percent of sodium hexametaphosphate (Calgon) solution and sufficient sulfuric acid to achieve a pH of 2.8 at the end of that time. This part of the process has become known as the Calgon pickle. The solution is reused daily, being regenerated with additional Calgon and sulfuric acid, and is discarded only once a year. The treatment presumably prepares the hides for a more rapid vegetable tanning process, and the recommended one with varied concentration of wattle (mimosa) takes 11 days. The tanning liquors are recirculated and reused. Further finishing of leathers that have been prepared by the Liritan process is the same as for those prepared by conventional processes. The Liritan polyphosphate-vegetable combination tannage process, as a non-effluent rapid tannage for sole leather, is used by sole-leather tanneries throughout the world.
U.S. Pat. No. 4,419,372 discloses a simulated raw hide product for dogs. In U.S. Pat. No. 3,408,918, a solution of phosphoric acid is used to neutralize excess calcium in limed hide pieces. U.S. Pat. No. 3,922,377 discloses a heat-processed, dehydrated, bacteriologically-stable pork rind product capable of rapid rehydration. The rehydrated rind is formulated in a pork sausage which includes sodium polyphosphate. German Patent No. 3,426,203 discloses a chewing article for dogs consisting of 92 volume parts of raw skin, 4 volume parts of lime and 4 volume parts of feed salts mixture containing (per 100 g) 700 mg of potassium, 1500 mg of carbonate, 1000 mg of calcium, 110 mg of phosphate, 40 mg of iron and 1 mg of iodine. The article is prepared from cow skin by stripping the skin, and subjecting the subcutaneous material to neutralization to pH 6, treating with a solution of iodine-containing feed salt and lime, shaping to form the article and drying.
U.S. Pat. No. 4,145,447 discloses a hard, unit-integral, unitized, self-contained, compact, chew-resistant nutritionally balanced animal food product having a density of at least about 0.5 oz./in..sup.3, a final water content of at least about 5.5 percent by weight, and a breaking force of at least about 60 psi. The animal food contains, for example, dried meals, dried fish, dried dairy products, fish meal, fish flour, cereals, flours, carbohydrates, dried fruits, etc., with or without food additives or supplements such as vitamins, minerals, medicinals, etc., for example chemicals, enzymes, etc., capable of removing plaque or tartar from the animals's teeth, etc.
U.S. Pat. No. 4,044,158 discloses the use of tetrasodium pyrophosphate as a chelating agent in semi-moist pet foods. The neutral chelating agent is used in a semi-moist pet food having a pH of from 6.3 to 7.2 and which comprises about 5 to about 50 percent by weight meat or meat by-products, about 15 to about 50 percent moisture, and about 1 percent to about 26 percent by weight vegetable protein. The vegetable protein, an amylaceous material, and the chelating agent, it is taught, forms a composition which replaces part of the caseinate binder customarily present in a semi-moist pet food. No mention is made of any antitartar effectiveness of the pet food.
U.S. Pat. No. 4,215,149 discloses a process for maintaining the palatability of a pet food by coating particulates having a moisture content of less than 15 percent with fat and then with a monoalkali metal or monoalkaline earth metal salt of phosphoric acid to make the food more palatable to cats. Exemplary salts are monosodium phosphate and monocalcium phosphate.
U.S. Pat. No. 3,639,569 discloses the use of a tris(phosphonoalkyl)amine in a dentifrice composition with a dentifrice abrasive selected from the group consisting of beta-phase calcium pyrophosphate, particulate thermosetting polymerized resin, alumina, sodium metaphosphate, and mixture thereof, or in a mouthwash composition, or in a chewing gum composition or dental prophylaxis paste composition. The patent discloses that the use of inorganic pyrophosphates as anti-calculus agents in oral compositions has the problem of hydrolysis in aqueous products and loss of activity prior to the termination of the normal shelf-life of such products. The patent also teaches that calculus inhibition by chelation of calcium ion may seriously damage tooth structure by decalcification.
U.S. Pat. No. 3,957,964 discloses microcapsules containing essential oils of mint flavor in a dentifrice adapted to release a plural flavor-burst signaling the onset of and the completion of a toothbrushing operation. The dentifrice may be a toothpaste having dicalcium phosphate as a polishing agent.
U.S. Pat. No. 3,959,458 discloses the use of from about 0.2 to about 8 percent by weight of an orally acceptable monofluorophosphate with an anticalculus agent which is a condensation product of ammonia and phosphorus pentoxide or with a polyphosphonate in an oral composition. The oral composition may further contain a calcium pyrophosphate abrasive. The patent teaches that sodium or calcium monofluorophosphate, when used in combination with the anticalculus agents, exhibit no detectable damage to silicate fillings in the mouth whereas other anticaries agents, such as sodium fluoride, do exhibit damage. It is also taught that below about pH 5.0 some of the anticalculus agents can damage dental enamel.
U.S. Pat. No. 4,314,990 discloses the use of a phosphate buffering agent, which provides phosphate ions to maintain the pH of a slurry in the range of about 6.8 to 8.0, in a toothpaste composition which comprises 6 to 45 percent of a silica dental abrasive, from about 0.01 to 3 percent of a fluoride ion source, from about 10 to 45 percent of water, and about 30 to 70 percent of a humectant.
U.S. Pat. No. 4,323,551 discloses the use of a tetraalkali metal pyrophosphate salt to provide from about 0.5 to 5 percent of the P.sub.2 O.sub.7.sup.-4 species in a mouthwash composition comprising 0.02 to 0.2 percent of a quaternary ammonium compound, and a carrier liquid wherein the pH is adjusted to about 7.0 to 9.5 with a mineral or organic acid.
U.S. Pat. No. 4,421,527 discloses the use of a precipitated amorphous silicon dioxide prepared by acidulation in an abrasive composition in a toothpaste that contains fluoride. Phosphoric acid is disclosed as an acidulant. Soluble phosphates, such as the pyrophosphates, are taught as improving fluoride pellicle penetration.
U.S. Pat. No. 4,515,770 discloses a process wherein a soluble source of phosphate ions or a soluble source of calcium ions is uniformally distributed through sucrose in crystalline form as a result of dissolution of the sucrose and soluble source of calcium or phosphate ions in water followed by evaporation of the water solvent. It is taught that it is of substantial importance that the calcium or phosphate ion source be as rapidly soluble in saliva as the sugar so that the protective ions will migrate to salivary retention areas as rapidly as the sugar. A material, it is taught, which is cariogenic by virtue of directly or indirectly participating in the lowering of pH in salivary retention areas is rendered non-cariogenic by treatment to incorporate enough of either a calcium or phosphate ion source to keep the acidic medium from dissolving the tooth enamel. It is also disclosed that systematically administered phosphates are said to differ in cariostatic activity depending on the type of anion (cyclictrimeta-, hexameta-, ortho-, and pyrophosphate, increasing in effectivness in that order). It is further taught that these developments have unfortunately resulted in only minor advances in prevention of carious degradation of teeth because none of the "remineralization" processes have been shown to be consistently effective.
U.S. Pat. No. 4,515,772 discloses the use of from about 10 to about 70 percent of a dental abrasive selected from the group consisting of insoluble metaphosphates, alumina, thermosetting polymerized resins, and silica from about 50 to about 3,500 ppm of fluoride ions from a fluoride ion source, and an amount of a pyrophosphate salt selected from the group consisting of dialkali metal and mixtures of dialkali metal and tetraalkali metal pyrophosphate salts sufficient to provide at least 1.5 percent of P.sub.2 O.sub.7.sup.-4. The pyrophosphate ion is provided by a mixture of disodium pyrophosphate and tetrasodium pyrophosphate. The fluoride ion source is disclosed as an essential component. The upper limits on the sodium pyrophosphate salts are determined by solubility considerations, while the tetrapotassium level is established for taste reasons. It is further taught that surprisingly mixtures of certain pyrophosphate salts can provide a safe and effective anti-calculus product while also not presenting difficult formulation problems.
U.S. Pat. No. 4,532,124 discloses the use of a plaque mineralizing aqueous solution comprising urea, a fluoride salt, a water-soluble calcium salt, and a water-soluble phosphate salt in the mineralization of dental plaque. It is disclosed that high plaque calcium and inorganic phosphate levels will lower the `critical pH`, that is, the pH which plaque must reach before it becomes unsaturated with respect to biological apatite, and enamel dissolution commences. The urea is metabolized by bacteria to produce alkali in plaque. Aspartame and amino acids may be substituted for the urea.
U.S. Pat. No. 4,540,584 discloses the use of coral sand as an effective component in a mineral supplement in an amount sufficient to provide calcium carbonate as a mineral supplemental for humans, such coral sand also containing PO.sub.4. The composition is useful for replenishing calcium and phosphorous, as well as other minerals. Acidic foods tend to result in decayed teeth and bone fractures because of calcium poverty.
U.S. Pat. No. 3,567,459 discloses conversion of a hot melt of sugar having a moisture content less than 5 percent to a dough-like bone-forming composition by incorporation of nutritional fillers, fatty flavoring materials, and fat-absorbing farinaceous materials. The composition is formed and cooled. The patent teaches mastication of bones provides teeth cleaning benefits stemming from abrasion and other contacts of bone fragments.
U.S. Pat. No. 3,701,830 discloses the use of a neutral protease enzyme for removing plaque from and preventing the formation of calculus on the teeth of dogs wherein the neutral protease is obtained by fermentation with a strain of Bacillus suptilis or Bacillus sterothermophilus.
U.S. Pat. No. 3,882,257 discloses a process where 75 percent by weight of bones is admixed with 23.5 percent by weight of animal by-products, and the mixture is bound with salt in the preparation of a pet food having about 40 percent natural animal protein. The product enables a dog to exercise his jaws and gums to remove tartar from teeth.
U.S. Pat. No. 3,899,607 discloses a dough mixture which is: worked and shaped at a temperature of 170.degree. to 220.degree. F. to form a simulated bone having a structural matrix; or cooked, dried to a moisture content of between 5 and 12 percent by weight, ground and mixed with a dextrin adhesive to form a simulated bone having a structural matrix.
U.S. Pat. No. 4,364,925 discloses that an enzyme for removing plaque and/or tartar from the teeth is included in a chew-resistant layer of an integral chew-resistant multi-layer animal food system having a structure supporting fibers. U.S. Pat. Nos. 3,194,738 and 3,686,393 also relate to the use of enzymes for inhibiting plaque.
U.S. Pat. No. 3,488,419 discloses the use of a polyphosphonate or salt thereof in compositions like dentrifices, mouthwashes, prophylaxis pastes and topical compositions. The patent teaches that inorganic polyphosphates, such as pyrophosphates, hydrolyze in aqueous products and do not remain in active form throughout the normal shelf-life of such products. Calculus and crystal growth inhibition tests on rats using calculus prophylaxis are disclosed. The patent also teaches that calculus inhibition by chelation of calcium ion may seriously damage tooth structure by decalcification.
U.S. Pat. No. 3,535,420 discloses the use of a cyclic tetraphosphonic acid as an anti-calculus agent in an oral composition. The patent teaches that inorganic polyphosphates, such as pyrophosphates, hydrolyze in aqueous products and do not remain in active form throughout the normal shelf-life of such products. It is also taught that, although certain of the art-disclosed chelators are purportedly safe for use on dental enamel, the chemical similarity of calculus to the tooth structure limits the usefulness of the chelation approach because the more effective chelators can seriously damage the tooth structure by decalcification. The cyclic tetraphosphonates are calcium sequestrants, but they retard calculus formation by a mechanism that is believed to involve the inhibition of hydroxylapatite crystal growth rather than calcium sequestering.
U.S. Pat. No. 3,686,393 discloses the use of a dextranase used to eliminate dental plaque formation.
U.S. Pat. No. 3,956,479 discloses the use of a quaternary ammonium compound having a carbamate, or a thiocarbamate, or a dithiocarbamate, or a carbamide group in an oral preparation. The compounds are effective in reducing caries and inhibiting formation of oral calculus.
U.S. Pat. No. 4,003,971 discloses the use of a dentifrice component in the production of dentifrice speckles. Antimicrobial agents for incorporation into oral dentifrice formulations may be effective by reducing dental plaque or inhibiting the formation of dental calculus.
U.S. Pat. No. 4,254,101 discloses the use of from about 6 to 45 percent of a silica dental abrasive, from about 30 to 70 percent of a humectant, and from about 0.03 to 1.0 percent of a carboxyvinyl polymer in a toothpaste composition. The use of optional anticalculus agents in amounts of from about 0.01 to 2.5 percent by weight of the toothpaste composition are taught.
U.S. Pat. No. 4,472,373 discloses the use of a pyridium salt as an anti-plaque agent in a flavored alcoholic carrier. Phosphates, such as calcium pyrophosphate, are disclosed as dentifrice abrasives.
U.S. Pat. No. 4,153,732 discloses the use of at least one soluble aluminum ion containing salt with adipic acid, ascorbic acid, or mixtures thereof as a cariostatic additive for comestibles. The patent teaches that calcium pyrophosphate and insoluble sodium metaphosphate abrasives coact with aluminum fluoride in dentifrice compositions.
U.S. Pat. No. 4,627,977 discloses an oral composition, such as, a toothpaste (including gel or cream), mouthwash, lozenge, chewing gum or tooth powder, containing a calculus-inhibiting amount of a linear molecularly dehydrated polyphosphate salt (e.g., a water-soluble alkali metal pyrophosphate) to inhibit enzymatic hydrolysis of said polyphosphate salt in saliva, a combination of a fluoride ion-providing source and a synthetic linear polymeric polycarboxylate. See also British Published Patent Application No. 2,180,157.
U.S. Pat. No. 4,678,662 discloses calcium carbonate particles coated with at least one pyrophosphate derivative, such as, disodium dihydrogen pyrophosphate and tetrasodium pyrophosphate.
European Published Patent Application No. 0236920 discloses a dentifrice comprising essentially insoluble calcium pyrophosphate as an abrasive and a clinically effective amount of soluble pyrophosphate, such as, tetrasodium pyrophosphate, or tripolyphosphate as an anticalculus agent.
U.S. Pat. No. 4,684,518 discloses a process for reducing the incidence of calculus on dental enamel. The enamel surfaces in the mouth are contacted with a composition comprising a soluble pyrophosphate source capable of providing at least 1.5 percent of P.sub.2 O.sub.7.sup.-4 and from about 50 to about 3500 ppm of fluorine.
U.S. Pat. No. 4,722,461 discloses an oral composition in the form of a mouthwash or liquid dentifrice comprising: an amount of a fluoride ion source sufficient to supply from about 50 ppm to about 3500 ppm of fluoride ions; an amount of a pyrophosphate salt selected from the group consisting of dialkali metal and mixtures of dialkali metal and tetraalkali metal pyrophosphate salts sufficient to provide at least 1.5 percent of P.sub.2 O.sub.7.sup.-4 ; and water. The pH of the composition is from about 6.0 to about 10.0. Calcium pyrophosphate is termed to be an abrasive. See European Published Patent Application No. 0097476.
British Published Patent Application No. 2,201,593 discloses an oral composition in the form of a toothpaste effective in reducing calculus comprising: a safe and effective amount of a soluble pyrophosphate salt or mixture of the salts; from about 5 to about 60 percent of a suitable toothpaste abrasive; an amount of a fluoride ion source sufficient to provide from about 50 ppm to about 3500 ppm fluoride; from about 5 to about 60 percent of humectant selected from the group consisting of sorbitol, glycerine, polyethylene glycols, mineral oil, and mixtures thereof; from about 0.3 to about 5 percent of a surfactant selected from the group consisting of alkyl sulfate surfactants, ethoxylated alkyl sulfate surfactants and mixtures thereof; and water. The composition has a pH of from about 6 to about 10, is substantially free of polyethylene glycols having fewer than six ethoxy units and short chain monohydric alcohols and has potassium ions present at a level of from about 0.5 to about 7 percent. The soluble pyrophosphate salt can be, for example tetrapotassium pyrophosphate, tetrasodium pyrophosphate, sodium acid pyrophosphate and mixtures thereof.
U.S. Pat. No. 4,806,340 discloses an oral dentifrice composition such as a toothpaste, dental gel, toothpowder, dental tablet or lozenge containing as anticalculus agent about 4.3 to about 7 percent of alkali metal pyrophosphates comprising at least 4.3 percent of tetrapotassium pyrophosphate alone or admixed with up to 2.7 percent of tetrasodium pyrophosphate, and as inhibitors against enzymatic hydrolysis of such agent in saliva, a fluoride and preferably up to about 3 percent of a synthetic anionic polymeric polycarboxylate. The composition is used in a program of oral hygiene and/or for inhibiting dental calculus. It is known that saliva contains acid phosphatase, alkaline phosphatase and pyrophosphatase enzymes. It is considered that any one of the three enzymes may adversely affect pyrophosphates as an inhibitor of hydroxyapatite formation and calculus. It is accordingly apparent that an anticalculus pyrophosphate dentifrice composition, should inhibit, reduce or nullify the destructive activity of all three salivary enzymes. See Also British Published Patent Application No. 2,182,244.
Australian Published Patent Application No. 168071 discloses a dialkali metal-alkaline earth metal pyrophosphate containing about 1 to about 5 percent by weight of chemically combined fluorine. The composition is a dentifrice base. The method of producing the fluorinated dialkali metal-alkaline earth metal pyrophosphate, which comprises reacting together, in the presence of an aqueous medium, a water-soluble metal fluoride, an alkali metal pyrophosphate (such as, tetrasodium pyrophosphate), and a water soluble alkaline earth metal salt. The reactants being employed in the proportions required to yield a dialkali metal-alkaline earth metal pyrophosphate containing about 1 to about 5 percent by weight of chemically combined fluorine.
British Patent No. 777,556 discloses a dentifrice composition which contains a fluoride compound which releases fluoride ions in water, a calcium polyphosphate polishing agent, and a calcium ion suppression agent to maintain the effect of the fluoride upon ageing.